Telephone-exchange apparatus



(No Model.) 2 Sheets-Sheet 1. J. J. OARTY. TELEPHONE EXCHANGE APPARATUS.

Patented May 13, 1890.

(No Model.) 2 ShetE-Sheet 2.

J. J. OARTY.

TELEPHONE EXCHANGE APPARATUS. No. 427,742. Patented May-13, 189E).

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UNITED STATES PATENT NICE.

JOHN J. OARTY, OF NEW YORK, N. Y., ASSIGNOR TO THE IVESTERN ELEC- TRIC COMPANY, OF CHICAGO, ILLINOIS.

TELEPHONE-EXCHANGE APPARATUS.

SPECIFICATION forming part of Letters Patent No. 427,742, dated May 13, 1890.

Application filed March 23, 1889. Serial No. 304,505. (No model.)

To aZZ whom it may concern: Referring now to Fig. 1, subscribers station Be it known that I, JOHN J. CARTY,a citizen 1 is connected with the central ofiice by a of the United States, residing at New York telephone-line a, consisting of two branches city, in the county of New York and State of or limbs a a The circuit of limb a may be 5 New York, have invented a certain new and traced through the spring and contact of useful Improvement in Telephone-Exchange springjack switch Z), and thence through one Apparatus, (Case 3,) of which the following winding of the convert-erbtothe contact-point is a full, clear, concise, and exact deseripof spring-jack switch 11 and thence to the tion,referencebeing had tothe accompanying spring of said switch 19 with which spring 1o drawings, forming a part of this specification. the other branch or limb a is connected and My invention relates to multiple switehthence over said limb a back to station 1.

board systems of telephone-exchange; and its The coil of converter 1), which is included in objects are, first, to reduce the amount of the circuit thus traced, is provided with a wiring required between the different boards, branch Ulwhich passes through the individual 6 5 I5 and, second, to reduce the size of the switches, annunciator I) of the line, and thence to so thatalargernumber oflines may bebrought ground. (For a detail of the apparatus at within the reach of each operator. station 1 see station 1, Fig. 2.)

My invention is particularly designed for The telephone-line c of subscribers station k use in connection with metallic-circuit tele- 2 consists of two branches or limbs 0 c limb 7o 20 phone-lines; and it consists in telephone-lines 0 being connected through spring-jack switch each connected with a different spring-jack (Z, and thence through a coil of repeating coil switch upon one of the switch-boards, each d, and thence the circuit may be traced line being connected, through an inductionthrough the contact and spring Of spring-jack coil orconverter,with metallicsockets on other switch (Z and thence to subscribers station 2 5 boards, one for each line on each of two or more 2 over limb 0 A branch d from the coil of other switch-boards. converter d, which includes circuit 0, extends, My invention consists, also,in apparatus for as shown, through individual annunciator (1" making the connections between trunk lines to ground. and the spring-jack switches upon the first It will be observed that the frames or test- 3o switch-board, together with certain details of pieces of the spring-jack switches b b are construction and combinations of parts hereelectrically connected; also, the frames of inafter described. switches d d of line 0. One coil of converter In the drawings, which are illustrative of b is included in the circuit of line a and a my invention, Figure l is a diagram showing coil of the converter cl in the circuit of line 3 5 two telephonelines, each connected with a c. The individual annunciator b of lineais different double spring-jack switch on the included in a wire 11 connected, preferably, first board and each, through the medium of with the center of the coil of converter b, a converter, with different metallic sockets on which is included in line a. The individual each of two other boards, each line being proannunciator d" of line '0 is in a similar man 4o vided with a different branch from one of the ner included in the branch (1 which extends coils of its converter, which branches extend to the center of that coil of d which is ineach through a different individual annuncluded in circuit of line 0. The other coil of ciator to ground, operators outfits being proconverter Z) includes a wire a, which extends vided at the boards containing the metallic to socket 6' upon board 2 and to socket e 45 sockets. Fig. 2 is a diagram showing two upon board 3. The second coil of converter subscribers stations and lines extending to d is included in like manner in a wire f, eX- the first board with apparatus for connectin g tending from ground through said coil to a said lines with a trunk-line. socket f on board 2 and a corresponding Like parts are indicated by similar letters socket f on board 3. ICC 50 and numerals of reference throughout the At board 2,1 have shown an operators outdifferent figures. fit consisting of a pair of connecting cords with terminal plugs g g, a cam-lever switch g a clearing-out annunciator connected between the two contact-sprin gs of the switch, the telephone g in a branch extending from ground through said telephone to the telephone-contacts of the switch 9 a pair of calling-keys g 9, included in circuit of said connecting-cords, and a test-plug 9 included in a ground branch, which ground branch includes one coil of an induction-coil g the other coil of said induction-coil being in a bridge across the telephone terminals. The test-battery g is included in the cord connecting with the plug 9. Similar operators apparatus is shown at board 3.

Referring now to the apparatus of the subscriber at stat-i011 2 it will be seen that when the telephone is hung upon the switch, as shown, the bell h and generator h will be included in the circuit of wire c-that is to say, the side or limb c is connected through the bell h and the generator h to the telephone switch, and thence to the lower contact 7L of the switch,and thence through key 71 to limb 0 On removing the telephone from the switch the lower contact h is opened and the telephone-contact 7&4 is closed, thus looping the telephone into circuit.

The individual annunciators of the local lines are preferably distributed on boards 2 3, &c., which are provided with the simple metallic sockets. The local connections will thus be made upon the boards 2 3, and not upon the board 1, which contains the double spring-jack switches 11 b d (Z This first board 1, I reserve for making the trunk or toll line connections, and it may be placed, if desired, in a room by itself. Thus in Fig. 2 I have shown two subscribers stations 1 and 2 connected with board 1 and a toll-line or trunk-line operators outfit. I will suppose that the long-distance lines are connected with a separate board 4. It is evident, however, that they might be provided with switches upon board 1, if desired. I have shown the metallic-circuit long-distance line 2' connected through spring-jack switch 2', annunciator 2' and thence through the other spring-jack switch i of the pair. It is necessary to be able to connect anyone of the longdistance linest' with any one of the local telephone-lines a c.

The calls of the different local lines will be received by the operators at the different local boards 2-3 in the usual manner. Any local operator receiving a call for an extra territolial line (as toll-lines and other lines not be longing to the local system are sometimes called) will notify the operator at board 4 of the call, giving the number of the subscriber calling and the number or name of the extra territorial line with which the calling subscriber has asked connection.

The connection between any local telephone-line, as line a, and any extra territorial.

line, as line 2', may be made by loop-plugs i '6 connected, as shown, by flexible cords when inserted, respectively, in switch device t of line 1' and the switch device I) b of line a. In this manner a local line and an extra territorial line may be looped together in metallic circuit without including in the circuit any unnecessary resistance.

In large exchanges I preferably place an operator at each of the boards 4 and 1, each being provided with a telephone-set so arranged that they can communicate with one another, as desired. Thus at board 1, I have shown telephone-set 2'", and at board 4telephone-set 17. The local telephone-line 7c is connected with telephone-set i and extends thence to terminals 75, and k on the different boards 1 2 3. The call from any of the local boards, as 1. or 2, is repeated over line 76 to the operator at board 4, listening at telephone z' The operator at telephone 2' by depressing the pair of keys Z, puts herself in communication with operator at board 1, listening at telephone 2'. The generator Z is connected with appropriate contacts of ringingkeys Z Z". By depressing Z current will be sent from generator I over any line i with which the twin plug 1 is connected. By depressing ringing-key Z that is, by forcing down the piston thereof-the generator Z is brought into circuit with the cords connecting with the different terminals of twin plug The operator at board 4 may thusring in either direction to signal over a long-distanee wire or over any local line with which she may be connected.

Each of the operators at the local boards is provided with a test-plug connected with her telephone for determining whether any line wan ted or called for is already connected or in use. Thus test-plu g m is provided at board 1, the circuit of which is connected with telephone set 6. Test plug g is provided at board 2, as before described, and a-test-plug m is provided at board 3, connected with the operators telephone 072 through a converter m I will now describe the manner of connect.- in g an y two local lines together upon one of the switch-boards 2 3. I will suppose that subscriber 2 wishes connection with subscriber 1. He depresses key it and turns generator h, thus sending current over limb 0' through switch (Z to coil (1 and thence over branch (1 through individual annunciator cl on board 3 to ground. The operator at board 3 seeing sh utter (1 fall, immediately lifts plug on and inserts the same into socket f corresponding to line 0. The listening-in switch m being thrown to the position shown, the telephone a will be brought into the circuit of wire f. The circuit thus formed may be traced from ground near telephone m through said telephone, thence to the telephone-contacts of listening-in key m thence to the springs of said listening-in key resting upon said contacts, and thence from the spring m through test-battery m and calling-key m to the cord of plug m Thisplug m being inserted in IIO socket f, the circuit may be traced over wire f through the winding of converter (1, included in the circuit of wire f, to ground. In the meantime the subscriber at station 2 has let go of key 7L3 and taken down his telephone. Contact 7L2 is thus opened, and the telephonecontact and local contact at h being closed the telephone is brought into the circuit of wire 0. The operator at board 3 and the subscriber at station 2 are thus brought into telephonic communication. The subscriber havin given his order, the operator first, by means of plug on, tests the line called for. If the line tested is busy, a click will be heard in telephone m when plug m is touched to the switch of the line tested. If, however, the line is free, she will hear no click.

I will assume that the line called for was line a and that the plug m having been applied to socket e no click was heard in the telephone. The operator thereupon inserts the other plug m of the pair in socket e and depressing key m" throws current over wire e, in the circuit of which is included one winding of the converter 1). This, in a manner well understood, will induce a current in the metallic circuit a, connected in the other coil of the converter, and thus the bell included in the circuit of line (L at station 1 (for detail see Fig. 2) will be rung. The subscriber at station 1, taking down his telephone, will disconnect his bell and bring his telephone into circuit. W telephonic com munication-that is to say, the loop or metallic circuit 0 will include the telephone of subscriber 2 and one winding of converter (1. The metallic circuit or loop a will include the telephone of subscriber 1 and a winding of converter 1). The wires e f, which include the other windings, re-

spectively, of the converter, will be connected together by means of the plugs m m and the flexible cords connected therewith. On throwing up the cam-lever of key m the cleariug-out annunciator 'm is brought into the circuit of the cords. Then the subscribers are through talking, either may clear out in the ordinary manner by hanging up his telephone and turning his generator. Supposing one of two lines connected upon board 3 should be called for at another boardas, for example, board 2it will be observed that the test-battery m is included in the circuit of wires cf when two subscribers are connected, as above described. There will thus be battery-current present at all the other sockets of the connected lines upon other boards. The operator then at another board, as board 2,bysin1ply touching the tip of plug g upon socketf' would get battery-current through the coil of converter g connected with telephone g". Thus a click would be heard in the telephone, and she would know that the line 0 was busy, and would inform the one who had asked for line 0 of the fact. It should be observed that the wire f is branched The two subscribers will then be in' to the frame of the double switch cl (1 upon the first board and the wire 6 is branched to the frame of the double switch 1112". Thus plug 1% may be used for testing at board 1. The loop-plug i at board 1 is provided with two tips, each tip being insulated froma metallic sleeve upon the shank of each of the two parts. These sleeves are connected with the test-battery n. hen, therefore, twin plug is inserted in the switch device of any line, the frame of said switch device with which the sleeves come in contact will be connected with battery it. Thus any line is made to test busy at all the boards when connection is made therewith at any of the boards, whether the connection be at the first board or at one of the local boards 2 3, V

I will suppose now that subscriber 2 wishes connection with a long-distance line, as line 'i, he will call the same as if he desired a local connection. Throwing down shutter d the operator will make connection, as before described, by means of plug m and find out what is wanted. Finding that it is a trunk-line connection wanted, the operator will apply the other plug on to socket k thus bringing herself into communication with the operator listening at telephone 2 of long-distance board 4:. She will thereupon inform longdistance operator that subscriber 2 wishes connection with long-distance wire t'. Operator at board t will thereupon depress key Z to connect with telephone t of operator atboard 1, and will tell operator at board 1 to make connection with line a of subscriber 2. This she will do by inserting twin loop-plug in double switch (Z (Z of line 0. Operator at board at will at the same time insert twin plug i into the switch t' 71 Byineans of calling-key Z current from generator Z may be sent over the long-distance Wire and by means of key Z current may be sent over the circuit of subscriber 2. By means of listening-key n operator at board 4 may bridge telephone 2' between the cords 72 01 One coil of the clearing-out annunciator n is included in cord 71 and the other coil in cord n. These coils, being wound in opposite directions, will act together upon the armature. If a call is sent in over a long-distance line, as line i, the shutter i will be thrown down and the operator, inserting twin plug i in double switch i i and throwing up the camlever of listening-key a, will bring telephone i into circuit. Having received the order, she will operate key Z and repeat the order tothe operator at board 1, and theoperator at said board 1 will, after having found that the line wanted is not in use, insert the twin plug corresponding to the one in use at board 4 into the double switch of the line wanted. The insertion of twin plug 1' will cause the line with which connection is thus made to test busy at all other boards, as boards 2 The test-plug m may be applied to socket it" whenever operator at board 1 wishes to connect with operator at board 4. The repeating coils or converters Z) d may consist each of two coils, say, having a resistance each of one hundred and sixty ohms.

It will be seen that any telephone-line connected upon the first board is cut off from the repeating-coil and all the connections in the remaining boards of said line. Thus connections with long-distance lines are practically free from resistance. For local connections, however, the small amount of resistance introduced into the circuit by the repeatingcoils will not be harmful. The ground branches 19 61 are preferably connected at the center of those coils of the converters b d which are included in the metallic-circuit telephone-lines, so that when these telephonelines are used for talking they will not be made noisy. The feature of this part of my invention is having the grounded annunciator branches connected with the metallic circuits at their neutral points-that is to say, at some point near. the center of resistance. An additional advantage in having the grounded annunciator branch connected at or near the center of resistance is that when the subscriber rings offthat is to say, when he turns his generator to signal the central office to disconnect current will not be sent through this grounded branch to operate the individual annunciator. The economy of my system when applied to very large exchanges will be apparent, since spring-jack switches upon the local boards are not required. The number of connections for each line upon the local boards being greatly diminished, the problem of cabling that is, of disposing of the wires at the rear of the boards-is made very simple. I

The busy test which I have shown is found to be satisfactory. Other systems might, however, be used with good results.

It is apparent that my invention admits of various other modifications which will readily suggest themselves to those skilled in the art, and I therefore do not limit myself to the details of construction described herein.

Having thus described my invention, 1 claim as new and desire to secure by Letters Patent- 1. The combination, with a telephone-line connected with a switching device upon the switch-board of a telephone-exchange, of a converter, one coil of said converter beingincluded in said telephone-line, a branch from said coil extending to ground and containing an individual annunciator upon one of two or more other switch-boards of the exchange, the other coil of said converter being included in a branch wire extending from ground through said other coil and having a connection or socket upon each of said other local boards.

2. A subscribers apparatus consisting of a telephone, a telephone-switch operated thereby, a bell and generator, and akey for ground ing the portion of the circuit containing the generator and bell, said circuit extending in two branches or limbs to the central station and including one coil of a converter, a branch from said coil to ground through an individualannunciator upon one of two or more switch-boards, a branch wire connected with ground and passing through the other coil of said converter and extending to a different socket or connection upon each of said switchboards, whereby the subscriber may signal the central office and bring his telephone into a metallic circuit including one of the coils of the converter, the voice-currents sent over said metallic circuit being induced upon the ground branch containing the other coil, substantially as and for the purpose specified.

3. A m etallic-circuit telephone-line including a subscribers outfit and a key for grounding one side or limb of said circuit to ground at the subscribers station, a converter at the central office having one coil-included in said metallic circuit, and a branch from the center of said coil through an annunciator to ground, whereby the subscriber on operating his grounding-key may complete a circuitfrom his station through said annunciator, substantially as and for the purpose specified.

4. The combination of a switch-board provided with double spring-jack-switch deviceswith which different telephone-lines are connected, each telephone-line being provided with a different converter and including a coil thereof, and each being provided with a branch extending from said coil of its converter to grofind through an individual annunciator upon one of several local switch-boards, a wire for each telephone-line including the other coil of the converter thereof and extending to a different switch or socket on each of the local boards and to the insulated frame of the double spring-jack device of its line upon the first board, a subscribers outfit upon each of said telephone-lines, an operators apparatus at each'of the local switch-boards, one or more long-distance or extra-territorial lines, and an operators outfit at the terminal of said longdistance or extra-territorial line connected with an operators outfit at the board contain ing the double spring-jack devices of the local lines, whereby an operator at one of the local boards on receiving a'call for an extra-territorial line may notify the long-distance operator thereof, whereupon the long-distance op erator, in conjunction with the operator at the first board, may connect the local line with the extra-territorial line in metallic circuit,and whereby the long-distance operator, upon receiving a call for connection with a local line, may test said local line and make connection therewith, substantially as and for the purpose specified.

5. A metallic-circuit telephone-line provided with a double spring-jacloswiteh device upon the first board and connected, through the medium of a converter, with other local switchboards, a long-distance line, provided also with a double spring-jack-switch device, and a pair of twin plugs and connecting-cords,

by the long-distance line and the local line may be looped together, substantially as and for the purpose specified. I

6. Atelephone-circuit consisting'in the combination of two wires, each of said wires being provided with a switching device upon the first board and connecting, through the medium of a converter, withthe local switchboards, a long-distance line also provided with a switching device, and connecting cords and plugs whereby the long-distance line and the local line may be connected together, substantially as and for the purpose specified.

7. The combination, with a telephone-line passing through a switching device at one section of a multiple-board and through one coil of a converter, of a branch Wire extending through another coil of said converter to all of the sections of said multiple-board.

8. A metallic circuit extending from asubscribers station to the central office and includin g at said central office one coil of a converter, in combination with a branch from said coil to ground through an electro-magnetic device and a branch circuit from ground at the central office including the other coil of said converteiysaid branch extending to one or more switch-connecting devices at the central oflice, substantially as and for the purpose specified.

0. A metallic-circuit telephone-line including a subscribers station provided with a generator and switching devices, in combination with a branch from the center of the resistance of said line at the central office through an annunciator to ground, whereby the subscriber may bring his generator into a grounded circuit including said annunciator, substantially as and for the purpose specified.

In witness whereof I hereunto subscribe my name this 19th day of February, A. D. 1889.

JOHN J. CARTY. \Vitnesses:

Q F. DE LYSLE SMITH,

W. S. ECKERT. 

